To comply with current and proposed requirements, the pilot or co-pilot of an aircraft must have access to a variety of vertical situation information from a number of sources to allow the vertical maneuvering situation of the aircraft to be accurately and quickly assessed.
The amount of vertical situation information which the pilot or co-pilot needs to assess is increasing with the imposition of new requirements intended to increase both the airspace capacity and the safety of air travel. The newer requirements include the Global Air Traffic Management (GATM) system for use in managing air traffic, Reduced Vertical Separation Minimums (RVSM) for reducing the vertical separation requirements between aircraft to increase airspace capacity, Traffic Alert and Collision Avoidance System (TCAS) advisories to alert pilots about potentially hazardous aircraft targets in the area, and the Enhanced Ground Warning Proximity System (EGPWS) to indicate ground contours to help maintain clearance.
The vertical situation information which must be presented to the pilot to allow him to fly and navigate the aircraft, and to meet these newer requirements, may include the position of the aircraft, the profile path angle of the aircraft, the altitude preselect provided by air traffic control, the decision height for a particular landing approach, the projected flight path, positions of waypoints along the flight path, positions and the degree of threat posed by nearby aircraft targets, the location and elevation of runways, the ground contour, the radio altitude, Baroset and Baroset altitude, the aircraft's vertical speed and vertical speed setting, and possibly free format messages from the air traffic controller. A pilot's need to assess all of this information within a common reference frame requires the pilot to expend much cognitive processing when the information is presented on a number of different displays using different formats.
In conventional aircraft instrumentation, the pilot must observe vertical situation information presented in different formats on separate displays in an instrument panel. For example, some of the information is presented as pictorial data while other information is presented as digital data. In order to assess the vertical situation, the pilot must assimilate the different types of data and formulate a mental image of what the vertical situation is with respect to ground clearance, altitude, flight path assignments, other aircraft traffic, and navigation.
For example, one conventional instrumentation system includes a separate electromechanical display for each piece of vertical situation information. The system includes separate Barometric Altimeter indicators, Radar Altimeter indicators, and Vertical Speed indicators. The pilot or co-pilot must examine the information from each display, and then generate a mental image to integrate the information and determine its interrelationships.
Another aircraft instrumentation system includes an electronic flight display with a separate display element for each piece of vertical situation information. These separate elements are presented using different formats such that each piece of information remains separate and disconnected from the other pieces. For example, traffic advisory information may be shown in a horizontal format, while altitude information is shown on a vertical tape. Thus, to assess the entire vertical situation, the pilot must still read the separate data which is presented in different reference frames, make mental translations of the separate data into a common reference frame, and then form a mental picture to integrate the data within this frame. This task requires much cognitive processing to assess the vertical situation, and leads to high levels of workload, stress, and fatigue. The need to make the mental translations may also lead to inaccurate results.
Accordingly, it would be advantageous to provide an improved aircraft instrumentation system for displaying the complete vertical situation of the aircraft. It would be advantageous to provide an instrumentation system wherein vertical situation information from a number of sources is presented and arranged to allow a pilot to rapidly and accurately assess the complete vertical situation with minimum cognitive processing.